With the achievement of long-lasting allogeneic bone marrow transplants it became possible to recognize a graft-versus-leukemia effect. This positive effect is enhanced with additional transfusion of lymphocytes from the original hematopoietic stem cell donor alone and can reinduce long-lasting remissions and achieve possible leukemia relapse cure. Many blood and marrow transplantation teams are exploring donor lymphocyte transfusion use for therapy against tumor-specific antigens, for enhancing the defense against infections, or for correction of an ailing immune system. The appropriate cell dose remains unsettled. The graft-versus-leukemia (GVL) effect of allogeneic donor lymphocyte transfusion is associated with graft-versus-host disease (GVHD) and myelosuppression, and the pre- vention of these complications is a continuing matter of concern. It seems likely that in the future, further refinements in the separation of GVL from GVHD will ensure that allogeneic BMT will increasingly be used as a tool to procure an effective leukemia relapse profylaxis.

        Key words: donor lymphocyte transfusion, graft versus leukemia effect, leukemia relapse, graft versus host disease